One of the by-products of our steelmaking operations is dust. But the recent installation of dust extraction units at our plants in Vereeniging, South Africa, and Ostrava, Czech Republic, has greatly improved the air quality in the surrounding areas
Vereeniging, South Africa
Vereeniging Works is one of the company’s oldest plants and has been producing steel since 1943. The plant’s age meant its dust emissions were particularly high compared with modern steelworks. The idea of a dust extraction unit was conceived in 2006, when Arcelor merged with Mittal Steel and the new company began to take steps to mitigate the environmental impact of the Vereeniging plant.
The project involved installing a dust emission abatement unit at the electric arc furnace (EAF) in the plant’s melt shop. The system combines wet cooling (quenching) techniques and bag filter technology to reduce both primary and secondary emissions from the melt shop, the EAF and two ladle furnaces. The project included a new roof design for the ladle furnaces, allowing more efficient capture of primary fumes.
The facility was commissioned at the end of 2009 and officially opened in June 2010. The dust above the Vereeniging site has since diminished, with the dust capture rate from the melt shop activities improving by 45%.
Ostrava, Czech Republic
ArcelorMittal Ostrava installed a de-duster system at its sinter plant in 2011. The CZK1bn (US$57m) investment has cut dust emissions from Sinter Plant North from 50mg/cu m (the legal limit) to less than 20mg/cu m. The plant’s total dust emissions from sintering, an important step in the production of liquid state metal, have dropped by 270 tonnes per year. In 2012, dust emissions reached a historic low of 584 tonnes which is one third of the what the emissions were when ArcelorMittal bought the site in 2003.
The de-duster is basically a large vacuum cleaner. Combustion products are siphoned off from electrostatic filters onto a special textile, which catches the dust particles.
The textile filters catch 70% more dust particles than the previous electrostatic filters, and mufflers installed in the huge pipes reduce the noise generated by the 24-hour filter operation by 15%.
Only six similar de-dusters are in operation in European sinter plants. The system used at Ostrava has an added reactor that captures not only dust particles, but also up to 60% of all sulphur dioxide and dioxins.
In 2011, the project won a prize awarded by the local Chamber of Commerce under the aegis of the Czech Ministry of Environment. The jury of experts rated the project as the most significant corporate endeavour in environmental protection in the Czech Republic.
A de-dusting facility is also planned for our Zenica steel plant in Bosnia and Herzegovina.